ElastiCache clusters should have automatic minor version upgrades enabled

How to fix it

• Interrupts service: Upgrades then apply in the maintenance window, where a cluster with no replica to fail over to is unavailable while its node is replaced.

In the console

ElastiCache → the cache → Modify → Maintenance → Auto upgrade minor versions

Auto upgrade minor versions

Enable; the setting is disabled below Redis OSS 6.0, so raise the engine version first on an older cluster

Maintenance Window

The quietest hours, since upgrades are applied then

With the AWS CLI

aws elasticache modify-cache-cluster --cache-cluster-id <cache-cluster-id> --auto-minor-version-upgrade --region <region>

With Terraform

resource "aws_elasticache_cluster" "this" {
  cluster_id                 = var.cluster_id
  engine                     = "redis"
  auto_minor_version_upgrade = true
}